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Damage Detection for Composites Using Time Reversal Method with Different Amplitudes of Excitation

J. ZHOU, Y. YANG, L. XIAO, W. QU, G. CHEN

Abstract


Matrix cracking and delamination may occur when composite structures are exposed to impacts. Generally, these crack interfaces remain contact closely. Such incipient damage may fail to be detected if the strain generated by the excitation is too small to open the contact interface. To overcome this deficiency, a new kind of damage detection for composites using time reversal method with different amplitudes of excitation is proposed. By applying different amplitudes excitation voltage on the piezoelectric (PZT) transducers which are used to generate and receive Lamb wave signal, an experiment is set to detect impact damage in a composite plate based on time reversal theory. Experimental results demonstrate that although the time reversal reconstructed signal is similar to which in an intact plate when a low amplitude excitation is applied, it does not indicate the presence of damage in the structure. When the excitation amplitude exceeds a certain threshold, the reconstructed signal would be different from the original excitation signal. Damage indexes of each path are defined with the correlation coefficient between the original excitation signal and the reconstructed signal. An imaging algorithm is developed to locate the impact damage in the plate. It turns out that the damage can be detected and located accurately.

doi: 10.12783/SHM2015/312


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